A Story on Sinatra's F*cking Confguration that Really,

Really Bothered Me!

1,000 speakers conference #6

Jun Iio

1,000 speaker conf #6 Copyright © Jun Iio 2

Sinatra

1,000 speaker conf #6 Copyright © Jun Iio 3

Problem● My lecture at Chuo University

– “Network Technologies (1)/(2)”– A hands-on training course using “Sinatra”

● Problem– Sinatra is quite easy to build an application– $ ruby main.rb [RET]

● a web server runs... but can not access from outside

– Only it can be accessed locally, so the hands-on has to be conducted in a pseudo network environment (in the last year's case)

1,000 speaker conf #6 Copyright © Jun Iio 4

Problems in the net?● Routers (and its upstream) are concealed!

– Sinatra uses #4567 port in its default confg– “Are there some bottlenecks in the net?”

?Network conf. is controlled by

IT-center

1,000 speaker conf #6 Copyright © Jun Iio 5

Problems in the server?● Server confguration ?

– Server is running on Ubuntu 13.04

● ufw (user frewall)– 22(ssh), 80(http), … well known port … OK– 4567 … NG!

● NMAP (port scanning)– “4567 is not open”

1,000 speaker conf #6 Copyright © Jun Iio 6

Problems in the server?● $ netstat -l [RET]

…tcp4 0 0 localhost.4567 *.* LISTEN…

● Umm? “localhost” ?

1,000 speaker conf #6 Copyright © Jun Iio 7

The problem is in the APP!!